Interpolation of Browse Intensity by White-Tailed Deer on Forested Communities of Apostle Islands National Lakeshore

Maragi, Frank

The Apostle Islands National Lakeshore (APIS) maintains regionally significant plant communities dominated by Canada yew (Taxus canadensis) in the lower canopy that are being threatened by a burgeoning white-tailed deer (Odocoileus virginianus) population. The natural experimental design on APIS presents a unique opportunity to investigate the effects of herbivory on forest structure and composition across a gradient in deer density. With an increased trend of deer occupancy across the archipelago and concern over the longevity of Canada yew populations, resource managers are confronted with the task of developing monitoring strategies and activation points designed to reduce the effects of deer overabundance on these communities. The current project was developed to investigate the spatial relationship between vegetation covertype and white-tailed browse intensity on Sand Island. The results suggest that deer are preferentially browsing in communities dominated by yellow birch and northern white cedar. The consequence of high levels of browse intensity across 28% of the island creates a situation of concern over the product of browsing activity. As the only major impediment to floristic communities, high deer densities may have a dramatic affect on forest succession and recolonization events. Furthermore spatial analysis techniques should be utilized to investigate multiple factors contributing to the spatial patterns observed on Sand Island.